Internal-combustion engine



J. DAVIDSON April 13,1926. T 1,581,002

INTERNAL COMBUSTION ENGINE Filed April 11, 1924 s Sheets-Sheet 1 Fig.1.

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% n lw qv 1 All 1! Q 53am? 4 Patented Apr. 13, 1926 1 UNITED STATES v 1,581,002 PATENT JOHN DAVIDSON, F TUTBURY, ENGLAND.

IN'rnnNAL-ooMBnsrIon interim.

a plication filedApril 11, 1924. Serial 110,705,916.

1 To all whom it may 00mm;

Be itv known that I, JOHN DAVIDSON, a British subject, residing at The Elms, Tutbury, Stafford, England, have invented cer tain new and useful Improvements in Internal-Combustion .Engines, of which the =combustion engine comprises two working cylinders connected at their inner ends by a common combustion chamber, working pistons. in: the worlringcylinders coupled to the crankshaft to reciprocate simultaneously in the same direction, a pump operatively connected to the crank shaft to reciprocate simultaneously in opposite direction to that of the working pistons, ports in one of the working cylinders connected to the pump and ports in the other working cylinder for the escape. of exhaust gases.

Additional pairs 01: working cylinders may be provided to act with the pump which is then connected to a crankpin to" balance both or all of the. pairs of working pistons.

Furthermore, according to my invention, I provide an internal. combustion engine with two or more pairs of working cylinders wherein the cylinders of each pair are con nested together by a common combustion chamber, with more than one pump forsupplying combustible mixture or scavenging air to the working cylinders, the operative connections between the working pistons and pump pistons on the one hand and the engine shaft on the other hand being arranged to cause the pistons to balance one another.

The pairs of working cylinders may be arranged in various different positions and a valve may be employed to control the pump or pumps.

In order that my invention may be fully understood and more readily carriediinto practice, I have caused tobe appended heree unto six sheets of drawings illustrating various examples thereof, wherein Fig. 1 is a view in elevation, partly in sec- Fig. 3 is a developed section: online AQ-A of Fig. 2 illustrating amodified arrange-:1 ment,

Fig. 4 is a plan, and Fig. 5 a verticalsec- 00 1 tion developed on theline'B B oflFigh 4. ofv a further modified form. i

Fig. 6 is a transverse section, and Fig. '1 a vertical section developed on line C-G of Fig. 6, showing a further modified form. 5

Figs. 8 and 9. arehorizontal andvertical sections respectively in diagrammatic form. of a further modification.

Figs. lOand 11 aretransverse and vertical modification." I

'Relerring to the drawings two workingcylinders 1 and 2. are'arranged,v lhecylim ders l and 2 are of equal diameter and. are

sectionsinidiagrammatic form ofa. further connected at their inward end' by a commoncombustion chamber 8. Pistons 4 and 5.are arranged to work in the cylinders 1 and 2 and are coupledby connectingrods 6 and 7 directly to one crank pinB ofa crank shaft 18. Consequently the two pistons 4 and 530 reciprocate together or simultaneously inthe same direction. 7 Y

Formed in thebarrel of the cylinder 2. is. a port-9 for the admission of the fuel, andin the cylinder 1 a portlO is formed tov allow rod 13 ,to a crank pin 14 of the crank shaft 18,, the a crank pin 14 being angularly displaced about degrees to the crank pin 8'. The barrelof the pump cylinder 11 has an entrance port 15 controlled by the pump piston 12, andanoutl-et port 16-connected 1 by a passage 17 to the inlet port 9 With a view to avoiding having to adopt hinged connecting rods, or formi ng'the crank pin endof one of the connectionrodswso as 1 to clip: the other inorder tokeep the cylinders in one line at right angles to the crank shaft, I stagger the working cylinders to a small extent. 1 Figures 1 to 3 illustrate a construction having staggered working. cylin- 1 ders wherein the two working cylinders 1, and 2 are placed one on each sidelof an line drawn at right angles to the crank-shaft;

through the centre of the crank pin 8, so that uncovers the port 15 leading to the fuel the ends of the connecting rods 6' and 7 engaging the crank pin 8 may be placed side by side on the one crank pin 8. e

The cylinder of the fuel distributing pump 11 is placed along side the working cylinders 1 and 2 and the piston 12 thereof is connected by the connecting rod 13 to the crank pin '14 which is situated directly opposite the crank pin of the working pistons In the case of any of the engines above described the fuel pump is of the single acting type, consisting of a plain piston 12 directly connected to its crank pin 14 in the well-known manner, and I make the pump ,piston 12 of equal weight to the two work- "ing pistons 4 and 5, and I also: makethe connecting rod 13 of the pump piston 12 ofequal weight-to the two connecting rods 6, and 7 .the working pistons 4 and 5, in order that good-balance may'be obtained.

" Figure 3 which showsthe working pistons4 and 5 and the pump piston 12 in different positions from those shown in Figures 1 and 2 illustrate how the pump piston by performing its inward stroke while the working pistons are performing their outward stroke acts to balance the working pistonswhich in turn act to balance the pump piston. The arrows indicate the passage of the gas or vapour before and after combustion. I

The fuel pump may be of thesingle acting valveless type, the inner end of the cylinder 11 being directly connected'by the suitable port 16 to the inlet port 9 of the working cylinder 2. A port 15 is formed inflthe barrel of the pump cylinder 11 adapted to be uncovered near the end of the outward-stroke of the pump piston 12, and I the carburetter or fuel supply is directly connected to thisport 15. r

The engine above described operates as follows :Assum1ng that the two working pistons 4 and 5; are at the inner end of the stroke or in the case ofa vertical engine "a'reat the top'of their stroke and the charge is" compressed in the common combustion chamber 3, the charge is fired and the two pistons 4 and 5 move outwards together.

,Thepiston 4 when nearing the end of the stroke uncovers'the exhaust port 10 and a1- lows the gases to escape and immediately afterwards the piston 5 uncovers the inlet port 9 allowing the charge to be admitted and drive out the-remainder of the exhaust gas. On the return strokeof the pistons 4 and 5 the 'chargeis compressed andfired and the same operation repeated."

During the upward'stroke ofthe working pistons 4 and 5 the pump piston 12 moves downwards thus creating a slight vacuum in the pump cylinder 11, but whennearing the outward end of its stroke it supply and draws in the charge. On the upward stroke this charge is slightly compressed and as will readily be seen, when the pump piston 12 is nearing the top of its'strokethef working piston 5 commences to open the inlet port 9, thus allowing the charge of fuel to be delivered into the working cylinders 1 and 2. It will be observed that while the working pistons 4 and, 5 are performingtheir outward stroke, the pump piston 12 is performing its inward stroke, the charge being thus compressed in the pump cylinder 11 preparatory to rushing into the working cylinders 1 and 2 when the inlet port 9 is uncovered by the working piston 5.

Only one arrangement of the engine has been described but it will readily be seen that this improvement may be applied to two or more crank engines, and in the case ,of the two crank engines it will be seen that one double acting pump piston would suflice,

although .I prefer to provide a separate pump for each pair of working cylinders.

Figures 4 and 5 illustrate an arrangement for a two crank engine wherein one pump is employed to supply all of the working cylinders. There are two pairs of working cylinders 1, 2 and 1, 2- the cylinders of each pair having common combustion chambers 3 and 3 respectively, and the cylinders 1 and 1 beingeach provided with an exhaust port 10 .and 10* respectively while the cylinders 2 and 2 are each provided with an inlet port 9 and 9 respectively. The pump cylinder 11 is arranged between the pairs of working cylinders and is provided connected is angularly displaced relative to both of the said crank pins, the arrangement being so chosen that the pump piston 12 and working pistons 4, 5, 4, 5 tend to balance one another. It will be observed from the relative positions of the working pistons that in this engine the .crank'pin to which the pair of piston 4, 5 operate is angularly displaced relative to the crank pin to which the pair of working pistons 4 and 5 operate.

It is preferable to use valveless pumps for engines of verysmall powers only, and I may, with a view to increasing the efficiency of small powered engines, and I prefer in all cases of larger powered engines to, use a;

piston type of valve driven by an eccentric formed with a fixed to the crank shaft of an engine provided with a piston type valve to control the fuel. In these figures 1 and 2 indicate working cylinders provided with working pistons 4 and 5. The working cylinder 2 has an inlet port 9 connected by a passage 18vto a piston valve casing 19. A pumpcylinder 11 is provided between the casing and the working .cylindersand has a pump piston 12. The pistons 4, 5 and 12 are connected by connecting rods 6, .7 and 13 respectively .to a crank shaft so .as-to balanceone anotherand a valve rod 20 is also connected to the crank shaftby means of an eccentric formed with or fixed on the crankshaft. The valve rod 20 is connected to .av valve 21, 22, 23 which controls a port 24 provided in the barrel of the pump cylin-' der 11. The piston valve consists of two end portions 21 and 23 fitting the bore of 5 the valve casing ,19'and of a middle portion 22 of reduced diameter. The outer end of the valve casing is connected by a pipe 25 tothe fuel supply or carburetter.

-In operation, the end 21 of the piston valve moves towards the crank shaft and uncovers the port 24 and the pump piston 12 draws the fuel into the cylinder 11. The end 21 of the valve prevents any possibility of the passage 18 communicating with the :pipe 25. Movement of the piston valve away from the crank shaft causes the end 21 to arrive between the port 24 and the pipe 25 and uncoverthe port 24 to the passage 18, the end 23 preventing any escape fromthe passage from the inner end of the valve casing 19. The piston 12 is then able to force .the fuel through the port 24 into the passage 18 from whence it passes through the inlet port 9 to the working cylinders. The arrows shown in Figure 11 indicate the path of the gases or vapour before and after combustion.

Figures 8 and 9 illustrate an example of a two crank engine wherein a pump is provided for each pair of working cylinders. A pump cylinder 11 is arranged along side the working cylinders 1 and 2, and a pump cylinder 11 is arranged alongside the worl ing cylinders 1 and 2 The pump piston 12 and the working pistons 4 and 5 are connected to crank pins 14 and 14 the angular positions ofwhich coincide with each other, while the pair of working pistons 4 and 5 and the pump piston 12 are connected to crank pins 8 and 8 respectively the angular positions of which coincide with each other but are angularly displaced 180 degrees relative to the crank pins 14 and 14*. The arrangement of the pump ports, inlet ports and exhaust o-rts is a duplication of the similar ports escribed with reference to Figures 3 and-4. The balanceiof this 7 two .crank engine is equally. 'as perfectas that ofa four cylinderengine Working on the four. cycle principle, while the turning. moment is also similar owing to. [engine working on .the two cycle principle. The economy and balance of this engine is there fore equal to that of a fourcylinder, four strokeengine and itfurthermore runs absolutely .silently.

Figures 10 and llillustrate another example of an engine provided with a piston type valve. The engine has a. pair of staggered working cylinders 1 and 2, and a pairof staggered working cylinders 1 and 2 A pump cylinder 11 is provided for the cylinders 1 and 2, while a pump cylinder 11 is provided for the cylinders 1 and 2. The crank pin 8 'to which the, pistons 4 and 5 belonging to the working cylinders 1 and 2 are connected is displaced 180 degrees relative to the crank pin 8 to which the pistons 4 and 5 belongingt'o the working cylinders 1 and 2 are connected; longing to the pump cylinder 11 is connected to a crank pin. 14 which is angularly displaced 180 degrees relative to the crank pin 8, while the piston 12 belonging to the pump cylinder 11 is connected to the crank pin .8.

A piston valve 2627-28 comprising two parts 26 and '28 jointed together by a reduced part 27and having a closed lower end is provided with a port 29 in the part 28. The valve 26 2728 is operated by an eccentric 29 provided on a lay shaft 30 which is driven from the crank shaft 18 by sprocket wheel and chain gearing, and controls three ports, 31, 32 and The intake ofthe valve is .situatedat tl' e top of: the valve casing 34' The port 32 is connected by a commonpassage or chamber 35' to both the inlet ports 9 of both pairs of working cylinders. The port 31 is connected-by a passage 36 to a port 16 in the pump cylinder 11*, and the port 33is connected by a passage 38 to a port 16 in the pump cylinder 11.

During each revolution of the crank shaft 18, the valve 262728 brings each pump cylinder once in succession into communication with the valve intake and each pump cylinder once in succession into communi- The piston 12 becation with the passage or chamber 35 which In crude oil engines, for eXampleDiesel engines and Semi-Diesel engines, the. pump or pumps'are employed forpumping the scavenging air only, and the fuel is introduced into the working cylinderslby other means, such as those in general use.

It is therefore to be understood that Where the word fuel is employed this is to :be understood as covering the construction wherein air only is supplied tothe working pistons by the working pump, oil or other fuel being injected into the, working cylinders when the said charge of air has been compressed by said working pistons approaching the top oftheir' compression strokes.

lVhat I claim is: Y Y

s 1. In an internal combustion engine the combination of a plurality of pairs of Working cylinders, each pair having a common combustion chamber, a working piston in each cylinder, a plurality of pumps each having a piston, means to reciprocate a pair of working pistons and a pump piston together in unison, and means to reciprocate another pair of working; pistons and another pump piston together in unlson, each pair of working pistons moving with'a" pump piston substantially tobalance the dynamic forces of the said other pistons,

means to supply fuel fromeach pump toone cylinder of each pair, and an exhaust port in the other cylinder of each pair.

2. In an internal combustion engine the combination of a plurality of pa rs of working cylinders, each pair having a common combustion chamber, a working piston 111 each cylinder, a plurality. of pumps each having a piston, means to reciprocate a pair of working pistons and a pump piston together in unison, and means toreclprocate another pair "of working pistons and another cally operated valve to time the supply of fuel from each pump to one cylinder of each pair, and an exhaust port inthe other cylinder of each pair. a 1 Y 8. In an'internal combustion engine, the combination of a crank shaft, a pair of Working cylinders arranged on a center line which is'inclined to the plane ofthe crank shaft, a combustion chamber common to said cylinders, a pair of working pistons, connections. between said pistons and said crank shaft, whereby the pistons move up and down in unison, a pump having a piston, and means for operating the pump piston in a direction opposed to that of the Working pistons. I

l. In an internal combustion engine, the combination of aplurality of pairs of Working cylinders, the center line of each pair of cylindersbeing arranged atan inclination to theplane of the crank shaft, a combustion chamber common to each pair of cylinders, pistons in the cylinders, means to reciprocate thepistons of each pair of cylinders simultaneously in the same direction, a plurality of pumps, pistons therein, me-

of one pair of working pistons, an inlet port in one cylinder of each pair and an exhaust port in the other cylinder ofsuch pair. 7

ture.

J'OHN'DAVIDSON.

In testimony whereof I afiix my signa-. 

